Bearing mount for vane rings of turboengines

ABSTRACT

The blades of the vane ring are supported in an axle housing which is fixed to the outside of the blade carrier. Each housing includes a spaced inner wall and outer wall which define a coolant chamber therebetween. The inner wall also terminates short of the outer wall to form an open-ended chamber for reducing the flow of heat from the working medium within the blade carrier.

w13,ss2,231

United States Patent [72] Inventor Ferdinand Zerlauth References Cited UNITED STATES PATENTS 9/1953 Buckland et al. 12/1961 Winterthur, Switzerland Appl. No. 779,545

3,013,771 Henny...... 3,367,628 2/1968 Fitton.... 2,950,084 8/1960 Perry.............

Primary Examiner-Henry P. Raduazo Attorney-Kenyon & Kenyon, Reilly, Carr & Chapin GS OF [54] BEARING MOUNT FOR VANE RIN TURBOENGINES 16 Claims, 6 Drawing Figs.

ng are supported in an tside of the blade carrier.

spaced inner wall and outer wall mber therebetween. The inner wall e outer wall to form an open-ended from the working medim m u e mw h f 8m 0 &0 w f M 0d a e hme ew h d o asdn g MMummn 0 m mkmowu ic m Sm mm m A wpflilr. w dm h hm C m B mmmm Am who 5 68 3nwm97 ll W i-l s 25 1 96 l d/ 4 0 1.. 0 F 6 F4 m m m7 m m m I m m m5 m m m m m4 0 n n u m m m n u .l u u l u u u u M u II n n 4 m m m n C C d I l I s i .n U h F l. .1 l. 2 1 0 s 5 5 .1 l. .1

160; 230/] 14 um within the blade carrier.

Pmunan JUHI 1 an 3; 5821231 SHEET 1 or 6 Inventor Papa/M4440 25/2400? SHEET 3 OF 6 In ventor I A 7 7 7 7 1/: V

PATENIEBJUN Hem 3.582.231

' sum s or 6 Fly. 5

Inventor .FEPD/NHND Z E PL [)0 TH ,4 frog/Mays BEARING MOUNT FOR VANE RINGS OF TURBOENGINES This invention relates to a bearing mount for vane rings of turboengines. More particularly, this invention relates to a bearing mount for vane rings having rotatably adjustable blades.

Turboengines have been known to employ vane rings in which a plurality of blades have been mounted for angular adjustment with respect to the plane of the vane rings by rotation about the longitudinal axes of the respective blades. Because of the adjustability of the blades, such turboengines, and in particular turbines, have advantageously been adapted during operation to heavy load changes within wide limits without undergoing any substantial loss in efficiency and flow disturbances. Conversely, however, with the use of adjustable blades, particularly at elevated temperatures, troubles have occurred in many instances in the blade bearings. For example, such blade bearings have been exposed to the detrimental effects as well as the heat of the working medium of the turboengines.

Accordingly, it is an object of the invention to remove the blade bearings of adjustable blades on a vane ring from the direct influence of a working medium within a turboengine utilizing such blades.

It is another object of the invention to mount the blades of a vane ring in housings fixed to the outside of the vane ring.

It is another object of the invention to cool the bearings and bearing mount of a blade of a vane ring.

It is another object of the invention to mount the blades of a vane ring in bearing housings which are easily accessible for maintenance arid repair.

Briefly, the invention provides a bearing mount for each blade of a turboengine vane ring wherein the bearing mount is fixed to the outside of a blade carrier of the vane ring remote from the working medium of the turboengine. The bearing mount includes an axle housing having an inner tubular wall which carries bearings for rotatably mounting an axle of a blade and an outer wall which closes off the housing. The inner wall is formed with respect to the outer wall so as to define a hollow space therebetween. To this end, the inner wall can be cylindrical and supported on the outer wall by at least two spaced annular supports. Further, the support closest the blade carrier is preferably disposed at a distance from the end of the inner and outer walls to form a second hollow space which, however, is open ended in the direction of the blade carrier.

The inner tubular wall accommodates, at least in the areas at the two extremities, a bearing bushing having a cylindrical bore. These bearing bushings are preferably formed of a plastic suitable for dry operation without any special supply of lubricant and suitable for elevated temperatures, for example, the commercially available plastic known under the name DU which is resistant up to temperatures of 280 C.

Further, at least one group of bearing mounts have a distributor line connected into the respective closed hollow spaces for circulating a coolant, such as air, through the closed hollow space in order to cool the bearings and axle housing. One or more bores are also provided in the annular support of these bearing mounts between the closed hollow spaces and open hollow spaces in order to introduce the coolant into the open hollow spaces. This allows the part of the axle housing most exposed to a rise in temperature to be supplied from the distributor line with a required amount of coolant. This embodiment can be further simplified by having the closed hollow spaces form a part of the distributor line, for example, by having the hollow spaces of each pair of adjoining housings interconnected by tube sections of the distributor line.

In order to prevent an escape of coolant from the axle housing into the space outside the vane ring, a seal is mounted at a point outside of the bearing remote from the blade between the axle journal of the blade and the axle housing.

Preferably, the axle housing is supported only with the outer wall on the blade carrier so that the inner wall and bearings are not directly supplied with heat by the blade carrier. Also,

the axle housing can be attached to the blade carrier by means of a flange which preferably surrounds the axle housing at a point distant from the blade carrier.

Since the inner wall terminates within the plane of the outer wall in the open hollow space traversed by coolant, the inner wall is further cooled. Further, a displacement body can be placed in the open hollow space of an axle housing to define a flat flow path of narrow cross section with the opposite surfaces of the inner and outer walls for the coolant. Such a displacement body can be made of sheet metal with a U-shaped cross section, the outer leg of which is of greater length than the inner leg so as to rest on the blade carrier. Bores can also be arranged in the extended length of the outer leg to permit the coolant to flow against the neck of the blade passing through the blade carrier.

These and other objects and advantages of the invention will become more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawings in which:

FIG. I illustrates a fragmentary cross-sectional view of a vane ring according to the invention taken on line II-of FIGS.

FIG. 2 illustrates a view taken on line II-II of FIG. 1;

FIG. 3 illustrates a view taken in the plane of line III-III of FIG. 1 of two adjacent axle housings;

FIG. 4 illustrates a view taken on line IV-IV of FIG. 1;

FIG. 5 illustrates a cross-sectional view of a modified blade design and coolant passageway according to the invention; and

FIG. 6. illustrates a modified connection between adjacent bearing axle housings for the coolant flow.

Referring to FIG. 1, the vane ring includes an annular blade carrier 1 and a plurality of blades, for example, 28, which are circumferentially spaced and carried on the blade carrier 1 substantially radially of the rotor shaft (not shown) in the ring plane III-III. The blade carrier 1 is formed with a bore 2 for each blade as well as with a recess 3 about the bore 2 forreceiving an axle housing 4 of a bearing mount. Each blade is formed with a part 5 which contacts the working medium, a neck 6 substantially within the plane of the blade carrier 1, a blade journal 7 and an axle journal 8 secured about the blade journal 7. The part 5 merges into the neck 6 at the lower end while the neck 6 which is provided with cooling ribs 23 merges into the blade journal 7 to form a one-piece blade. This blade is further either forced into the journal 8 or is shrunk on by undercooling. Alternatively, the blade and journal 8 can be made as a compound cast element, for example, by precision casting and by forming part 5 of a heat resistant steel and by forming the other parts, particularly at the bearing surfaces, of a material having suitable dry operation properties.

Each axle housing 4 is individually secured to the blade carrier 1 and is formed with an inner wall 9 of tubular shape which carries a pair of bearings 10, 11 in supporting relation to the axle journal 8. The axle housing 4 is also formed with an outer wall 20 by which the axle housing 4 is supported in the recess 3. The outer wall 20 also supports the inner wall 9 at two spaced points via annular supports 12, 13 while forming an open hollow space 14 and a closed hollow space 15 between the walls 9, 20. The open hollow space 14 is situated at a point closer to the blade carrier 1 than the closed hollow space 15 while being in facing relation to the blade carrier 1.

Referring to FIGS. 2 and 3, the closed hollow spaces 15 of at least one group of axle housings 4 are interconnected by means of pipes 17 and together constitute a distribution line.

16 which supplies each one of the connected axle housings 4 with a partial amount of a gaseous coolant, for instance, air. To this end, at least one of the housings 4 connected to the distribution line 16 is further connected with a supply line 19 (FIG. 2) which provides the total amount of gas required for the cooling of all the housings 4 connected to the distribution line 16. Alternatively, two supply pipes can be attached to the lower half of the blade carrier and connected to the two axle housings 4 next to their respective axial separating planes. Following joining of the lower and upper half of the blade carrier and installation of the connecting pipes 17, an inherently closed distribution line 16 is produced with two substantially diametrically opposite supply connections. During inspection and cleaning operations of the vane rings, the supply lines need not be removed.

Referring to FIG. 1, the open hollow space 14 and the closed hollow space 15 which forms a part of the distribution conduit 16 in each housing are interconnected by means of bores 18. These bores 18 allow the partial amount of the cooling gas required for each axle housing 4 to be branched off from the distribution line 16 to the individual cooling sites.

Referring to FIGS. 1 and 4, a displacement body 39 of U- shaped cross section and discontinuous length is mounted in the open space 14 in inverted manner to form a pair of narrow coolant flow passages with the walls 9, 20. The outer leg of the body 39 is of greater length than the inner and rests on a plate 22in the recess 3 of the blade carrier 1. Bores 38 are provided in the lower end of this outer leg to permit coolant flow towards the blade neck 6.

With regard to the bearings 10, 11 affixed at both ends of the cylindrical bore formed by the inner wall 9, such are formed of a plastic capable of withstanding dry operation free of lubricants as well as elevated temperatures, for example, a plastic known as DU. Such plastics are able to withstand temperatures up to 200 C. and above without suffering any damage, and exhibit slide properties which do not make it necessary to provide for a special supply of lubricants. Likewise, the axle journal 8 designed for these bearings must be made of a material capable of sliding without wear and without a special supply of lubricants on a bearing plastic selected in this manner without either impairing itself or the bearings l0, l1.

Each axle housing 4 includes a peripheral flange 21 near the base of the outer wall which facilitates tightening of the housing 4 against the blade carrier 1 and the plate 22 positioned therebetween. The flange 21 surrounds the axle housing 4 at a distance from the blade carrier 1 so as to minimize the transmission of heat from the blade carrier 1 to the axle housing 4.

Additionally, the opposite end of the axle housing 4 has a thrust bearing mounted between the axle journal 8 and the housing 4. The thrust bearing includes a rotor disc 24 secured to the journal 8, a pair of sliding discs 25 on opposite sides of the rotor disc 24, and a mounting plate 26 secured on the housing 4 over the discs 24, 25. A sealing ring 55 is further mounted in a groove of the disc 26 to prevent an escape of cooling gas out of the axle housing 4 along the journal 8 into the space surrounding the blade carrier 1.

A hub 27 of an adjustable lever 28 is keyed over the end of the journal 8 to sealingly engage the sealing ring and to clamp the rotor disc 24 and the sliding discs 25 together against a shoulder 29 of the axle journal 8 so that the discs 24, 25 follow the rotational motions of the journal 8 and lever 28.

The cooling ribs 23 on the neck 6 of the blade are surrounded by a sleeve 30 mounted with a slight clearance within the plate 22. The sleeve 30 is compressed at one end by means of the spring 31 against a recess 32 of a ring segment 33 of the blade carrier 1 and is prevented from falling out of the plate 22 by means of a circlip 34 in a groove at the other end. One the other hand, the sleeve 30 is fitted tightly onto the cooling ribs 23 so as to be centered by the blade free of resistance in the plate 22. A plurality of bores 39 are provided in the sleeve 30 to communicate the opposite sides of the sleeve with each other. The cooling ribs 23 are provided with milled sections 35 alternating from rib to rib by a semicircumference and thereby face each other in two groups.

In operation, the cooling air supplied over the supply line 19, for instance at a temperature of approximately 130 C., and distributed into the open space 14 passes with increased speed in a thin layer between the displacement body 36 and the inner and outer walls 9 and 20, respectively, toward the blade neck 6; the cooling air flowing along the outer wall 20 being directed by means of the bores 38 in the displacement body leg toward the blade neck 6. The cooling air is then subdivided into two halves between the cooling ribs 23 by means of the milled sections 35 and passes around the one and the other side of the blade neck. Opposite the input point at the first cooling rib 23, the two halves of coolant flow join again in the milled section 35 of the second cooling rib 23. Following passage through this second milled section 35, the air separates again into two halves and flows in this manner between the second and third ribs of the blade neck. After leaving the intermediary space bordering the last rib, the air passes on through the bores 39 of the sleeve 30 into the space surrounding these bores and flows then through ducts (not shown) into the flow passage of the work medium within the blade carrier 1.

As a result of the structural design described and the guidance of the cooling air, the bearing points of the blades, in particular the bearing 10 situated closest to the blade carrier 1 and, hence, to the flow of the work medium, can be kept at a temperature capable of insuring trouble-free operation.

The cooling gas also acts simultaneously as a blocking gas for the axle housing 4 in view of the fact that its pressure must always be greater than the pressure of the working medium in the rotor space. This prevents the penetrating of working medium or residues thereof into the axle housing 4 and, as a result of impurities or foreign substance that are carried along, in particular upon running in of the engine, the soiling of the bearing surfaces of the axle journal 8. In addition, because of the seal 55, the space between the inner wall 9 and the axle journal 8 is sealed off with respect to the space surrounding the blade carrier 1 so that even in the case of a possible overpressure of the working medium, the working medium is prevented from passing through along the bearing surfaces.

During some phases of operation of the turboengine, the part 5 contacted by the working medium can have a temperature up to 600 C. and more. As a result, a flow of heat can be produced over the blade neck 6, the blade journal 7, the axle journal 8, and the bearings 10, 11 against areas ofa lower temperature at the outside of the engine. However, this heat flow is substantially reduced ahead of the bearing 10 as a considerable amount of heat is drawn off by the cooling air at the cooling ribs 23 before the heat reaches the blade journal 8. An additional heat transmission loss of the heat flow can be achieved by reducing the cross section of the blade journal 8 and blade neck 6 by means of a central bore 40 in the blade and, as a result, the conduction cross section of the heat flow.

Further, during operation, the bearing sleeve 10 cooled from the outside by means of the cooling air passing along at the free end of the inner wall 9. At the same time, the part of the cooling air passing along the inner side of the outer wall 20 reduces the influx of heat from the blade carrier 1 through the outer wall 20 onto the supports 12, 13 of the inner wall 9 and hence to the bearing sleeves 10, 11.

The combination of these above provisions guarantees a temperature for the bearings 10, l 1, that is, below 200 C. and thereby removes the risk of the occurrence of trouble.

Referring to FIG. 5, where the blade is manufactured as a compound casting element, a metallurgical connection is produced between the blade part 5 contacted by the work medium and the axle journal 8 in the area of the blade neck 6, for instance at the point 41 as shown. At this connection point, an alloy is produced along a short stretch of the two different parts so that, after completion of the cast element, the blade appears as a single workpiece that can be machined. The compound casting is arranged in such a way that the alloy site is at a point at which at least the work medium cannot supply any additional heat to the blade and, conversely, at which the blade is not yet fitted in a bearing.

Especially in the case of blades manufactured as compound castings, and also in the case of blades in which the two different materials have been interconnected mechanically by forcing or shrinking onto one another, it may be preferable to directly cool at least the bearing 10 of the axle journal 8 situated closest to the passage of the work medium. To this end, the axle journal 8 is reduced in diameter at the point 42 and a bearing tube 43 is slid over the reduced portion and welded to the axle journal 8 to form a hollow space 44 and receive the bearing sleeve 10. This hollow space 44 is connected by bores 45 in the journal 8 to the space 46 surrounding the blade neck 6 and, in addition, by means of radial bores 47 in the journal 8 with a central bore 40 in the journal 8. The central bore 40 leads into the open so that a partial amount of the flow of coolant determined by a dosing drum bore (as bore 55 in FIG. 1) is diverted in the space 46 and guided through the hollow space 44. As a result, the bearing tube 43 and the plastic bearing fitted thereon are efficiently cooled.

Referring to FIG. 6, the expansion pipes 17 can be of a length that is greater than the spacing between adjoining housings 4. That is, the expansion pipes 17 can be installed between the bearing housings 4 by, means of a suitable tool and be then expended against the housings 4. The expansion tubes 17 are thus urged elastically against the openings 48 of the axle housings 4 and are also pressed against the openings 48 as a result of internal pressure. In order to facilitate gripping and compression by a special tool, connecting flanges 49 are connected to the ends of the expansion pipes 17 and are preferably provided with collars 50 to form gripping surfaces.

As a result of the placing of the blade bearings in a housing outside the blade carrier, the bearings are removed, first, from the direct influence of the work medium. Second, so much heat is removed from the bearing housing and, indirectly from the bearings by means of a coolant that the bearing surfaces themselves will have a temperature that excludes their being subjected to damaging. Furthermore, the control of the various bearing points as well as possible replacement of defective elements is substantially simplified.

I claim:

1. In combination, a vane ring having a blade carrier and a plurality of blades passing therethrough, each said blade having an axle journal extending outwardly through said blade carrier to the outside thereof; and a separate bearing mount for each blade radially removable therefrom, each bearing mount having an axle housing fixed to said blade carrier on the outside thereof, said axle housing rotatably supporting said axle journal therein with respect to said blade carrier, and including means for removably mounting each said bearing mount individually on a respective blade whereby each said bearing mount can be removed from said carrier.

2. In combination, a vane ring having a blade carrier and a plurality of blades passing therethrough, each said blade having an axle journal extending outwardly through said blade carrier to the outside thereof; and a bearing mount having an axle housing fixed to said blade carrier on the outside thereof, said axle housing rotatably supporting said axle journal therein with respect to said blade carrier and including an inner tubelike wall and an outer wall defining the exterior of said housing and which further includes at least one bearing mounted on said inner wall in supporting relation to said axle journal.

3. The combination as set forth in claim 2 wherein said axle housing further includes at least two annular supports supporting said inner wall on said outer wall in spaced relation to define a closed hollow space therebetween, said annular support closest said blade carrier being spaced inwardly of the adjacent ends of said inner and outer walls to define an openended hollow space therebetween facing said blade carrier.

4. The combination as set forth in claim 3 further comprising a distribution line connected to each said closed hollow space of at least one group of axle housings for introduction of a coolant thereinto.

5. The combination as set forth in claim 4 further comprising a pipe section interconnected to said closed hollow spaces of each pair of adjoining axle housings.

6. The combination as set forth in claim 4 wherein said annular support closest saidblade carrier includes a dplurality of bores communicating said closed hollow space an said openended hollow space with each other for the flow of coolant therebetween.

7. The combination as set forth in claim 2 wherein said inner wall mounts a bearing sleeve at each end thereofin supporting relation to said axle journal.

8. The combination as set forth in claim 7 wherein each bearing sleeve is made of a heat resistant plastic material characterized in being free ofa lubricant supply.

9. The combination as set forth in claim 2 further comprising a seal between said axle housing and said axle journal on the side of said bearing opposite said blade carrier.

10. The combination as set forth in claim 2 wherein said outer wall is mounted on said blade carrier to support said axle housing thereon.

11. The combination as set forth in claim 2 wherein said inner wall terminates at the end closest said blade carrier at a point within the plane of said outer wall.

12. The combination as set forth in claim 2 wherein said inner and outer wall define an open-ended hollow space therebetween facing said blade carrier and which further comprises a displacement body in said hollow space forming a flat narrow passage along the surfaces thereof opposite each of said inner and outer walls and means for introducing a flow of coolant into said hollow space to flow through said flat narrow passages.

13. The combination as set forth in claim 12 wherein said displacement body is made of sheet metal.

14. The combination as set forth in claim 13 wherein said displacement body is of U-shaped cross section, the outer leg of said body being of greater length than the inner leg and being supported on said blade carrier, said outer leg including bores adjacent the end thereof communicating opposite sides of said leg with each other for a flow of coolant towards said blade.

15. ln combination, a vane ring having a blade carrier and a plurality of blades passing therethrough, each said blade having an axle journal extending outwardly through said blade carrier to the outside thereof; and a bearing mount having an axle housing fixed to said blade carrier on the outside thereof, said axle housing rotatably supporting said axle journal therein with respect to said blade carrier and including a peripheral flange spaced from said blade carrier for mounting of said axle housing on said blade carrier.

16. The combination as set forth in claim 1 wherein said axle housing further includes means for conducting a coolant therethrough for cooling said axle journal therein. 

1. In combination, a vane ring having a blade carrier and a plurality of blades passing therethrough, each said blade having an axle journal extending outwardly through said blade carrier to the outside thereof; and a separate bearing mount for each blade radially removable therefrom, each bearing mount having an axle housing fixed to said blade carrier on the outside thereof, said axle housing rotatably supporting said axle journal therein with respect to said blade carrier, and including means for removably mounting each said bearing mount individually on a respective blade whereby each said bearing mount can be removed from said carrier.
 2. In combination, a vane ring having a blade carrier and a plurality of blades passing therethrough, each said blade having an axle journal extending outwardly through said blade carrier to the outside thereof; and a bearing mount having an axle housing fixed to said blade carrier on the outside thereof, said axle housing rotatably supporting said axle journal therein with respect to said blade carrier and including an inner tubelike wall and an outer wall defining the exterior of said housing and which further includes at least one bearing mounted on said inner wall in supporting relation to said axle journal.
 3. The combination as set forth in claim 2 wherein said axle housing further includes at least two annular supports supporting said inner wall on said outer wall in spaced relation to define a closed hollow space therebetween, said annular support closest said blade carrier being spaced inwardly of the adjacent ends of said inner and outer walls to define an open-ended hollow space therebetween facing said blade carrier.
 4. The combination as set forth in claim 3 further comprising a distribution line connected to each said closed hollow space of at least one group of axle housings for introduction of a coolant thereinto.
 5. The combination as set forth in claim 4 further comprising a pipe section interconnected to said closed hollow spaces of each pair of adjoining axle housings.
 6. The combination as set forth in claim 4 wherein said annular support closest said blade carrier includes a plurality of bores communicating said closed hollow space and said open-ended hollow space with each other for the flow of coolant therebetween.
 7. The combination as set forth in claim 2 wherein said inner wall mounts a bearing sleeve at each end thereof in supporting relation to said axle journal.
 8. The combination as set forth in claim 7 wherein each bearing sleeve is made of a heat resistant plastic material characterized in being free of a lubricant supply.
 9. The combination as set forth in claim 2 further comprising a seal between said axle housing and said axle journal on the side of said bearing opposite said blade carrier.
 10. The combination as set forth in claim 2 wherein said outer wall is mounted on said blade carrier to support said axle housing thereon.
 11. The combination as set forth in claim 2 wherein said inner wall terminates at the end closest said blade carrier at a point within the plane of said outer wall.
 12. The combination as set forth in claim 2 wherein said inner and outer wall define an open-ended hollow space therebetween facing said blade carrier and which further comprises a displacement body in said hollow space forming a flat narrow passage along the surfaces thereof opposite each of said inner and outer walls and means for introducing a flow of coolant into said hollow space to flow through said flat narrow passages.
 13. The combination as set forth in claim 12 wherein said displacement body is made of sheet metal.
 14. The combination as set forth in claim 13 wherein said displacement body is of U-shaped cross section, the outer leg of said body being of greater length than the inner leg and being supported on said blade carrIer, said outer leg including bores adjacent the end thereof communicating opposite sides of said leg with each other for a flow of coolant towards said blade.
 15. In combination, a vane ring having a blade carrier and a plurality of blades passing therethrough, each said blade having an axle journal extending outwardly through said blade carrier to the outside thereof; and a bearing mount having an axle housing fixed to said blade carrier on the outside thereof, said axle housing rotatably supporting said axle journal therein with respect to said blade carrier and including a peripheral flange spaced from said blade carrier for mounting of said axle housing on said blade carrier.
 16. The combination as set forth in claim 1 wherein said axle housing further includes means for conducting a coolant therethrough for cooling said axle journal therein. 